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Matt
Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 21615
Experience:  BEng hons Mech engineering, in auto industry 22 years
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2.5 s type jag,2002 Loss of water pushing water out ,pressurising

Resolved Question:

2.5 s type jag,2002
Loss of water pushing water out ,pressurising both heater pipes from heater valve are cold,heater blows cold top and bottom hose hot
Then heater will blow hot sometimes and all pipes are hot and no water loss?
Could problem be circulation ??
Submitted: 2 years ago.
Category: Jaguar
Expert:  Matt replied 2 years ago.
Hello

if its pushing water out then either its still gassing up from combustion gas or its got an airlock or the water pump is failing

1st thing to try is a head gasket / block test kit as these take a coolant sample and analyse it for any signs of combustion gas - if present this would indicate the head gasket is on its way out

http://www.uktools.com/block-tester-p-12508.html

if this is OK then check that you've got all the air out of the system as this sort of episode can leave pockets of air trapped and prevent the coolant from circulating properly.

So check that the small hoses that run from the top of the engine and radiator that run back to the header / expansion tank are free flowing and not blocked

If these are OK then remove the tank pressure cap and run the engine from cold with the heater set to full hot

As the engine starts to warm, squeeze the large hoses running to the radiator to help displace any air - all the time keeping an eye on the level in the header tank, making sure it doesn't drop below the minimum and open any bleed screws built into the top cooling hoses - closing them off as soon as they start to gush water

Once the engine is up to temperature the tank should be quite full. Switch the engine off and leave it to cool

Then top up to the mark once its all cold and replace the cap

If you still have a problem then check that the water pump impeller / turbine isn't spinning on its shaft. You should be able to achieve this by removing the bottom hose from the engine and use a screwdriver or similar to feel for the water pump impeller blades, whilst your assistant turns the engine over by hand.
If you can stop the impeller with slight pressure from the screwdriver the pump needs replacing.
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